Process of converting oils



Feb. 5 1924;

, A. M D. M AFEE PROCESS OF CONVERTING OILS Patented Feb. 5, 1924.

UlTED STATE ALMER MOD. MOAFEE, 01 PORT ARTHUR, TEXAS, ASSIGiNOR TO GULF REFINING COM- PANY, OF PITTSBURGH, PENNSYLVANIA, A. CORPORATION OF TEXAS.

PROCESS OF CONVERTING OILS.

Application-filed March 29, 1922. Serial Np. 547,812.

To all whom it may concern:

Be it known that I, ALMER MODUFF'IE MCAFEE, a citizen of the United States, residing at Port Arthur, in the county of Jefferson and State of Texas, have invented certain new and useful Improvements in Processes of Converting Oils, of which the following is a specification.

. This invention relates to processes of converting oils; and it comprises a method of heating high boiling petroleumoils with anhydrous aluminum chlorid to produce oils of lower boiling point wherein the heating is intermittent, a charge of oil and of chlorid being run to a point where all volatile material is expelled from the charge with partial cooling of the vapors to condense aluminum chlorid prior to final condensation of the cooled vapors to give low-boiling oils, the

aluminum chlorid condensed in the partial cooling in the final stages of the run being then added to a fresh charge of oil and another distillation begun; all as more fully hereinafter set forth and as claimed.

Anhydrous aluminum chlorid is a solid, rather volatile body not particularly soluble in petroleum oils but exercising an energetic action thereon of the type known as catalytic, rearranging the constituent elements or groups of the contained hydrocarbons into new groupings. This property is utilized in a prior but copending application,

Serial No. 792,615, filed September 30, 1913,

for the manufacture of low boiling oils, such as gasoline, or of gasoline and kerosene from higher boiling oils said application disclosing but not-claiming specifically certain matter disclosed and claimed herein. In an embodiment of my invention specifically described and claimed therein, a high boiling petroleum oil, such as gas oil, is heated in the presence of a small amount of aluminum chlorid, say, 5 per cent on the amount of oil in the still; the vapors being sufiiciently cooled prior to their exit from the system to condense volatilized aluminum chlorid. With a vapor exit "temperature of about 300, the product is substantially all gasoline'; with an'exit temperature around 350 0 F., it is a mixture ofv gasoline and kerosene which can be separated by a subsequent redistillation. In this operation, the aluminum-ichlorid, which melts down with some of the oil in the still to form a heavy im- 5 miscible liquid, is kept in a state of suspen-' sion or emulsification by agitation. The operation as so far described is substantially a continuous one. The volume of oil may be kept substantially constant byadditions of fresh oil to compensate for that converted into lower boiling oils and removed. From time to time, as the aluminum chlorid loses its initial high activity, it is allowed to settle and is removed, fresh aluminum chlorid being added. The aluminum chlorid removed is sent to a recovery plant where it is heated to volatilize out and regain the contained aluminum chlorid.

In another embodiment of my invention, described but not specifically claimed in said application No. 792,615, the process in lieu of being a continuous operation was discontinuous, a charge of oil and aluminum chlorid in a still'being run todryness or formation of coke without additions of fresh oil sufiicient to compensate for oil volatilized and removed as gasoline, or as gasoline and kerosene, as the case might be. Otherwise the operation was the same, vapor temperatures at the point of exit being controlled to prevent volatilized aluminum chlorid reaching the final condensing system. This mode of operation presents certain advantages with some oils, and particularly those of heavy and viscous nature, such as certain topped heavy crudes. With these oils, because of their viscous character agitation presents difiiculties and these difficulties increase if there be a progressive supply of more oil to the body of material in the still. With Such oils it is better to run the charge to dryness, using an ordinary cokingstill, remove the coke and recharge. The present invention relates to such a method. It offers the advantage that the recovery of aluminum chlorid can be effected inthe same apparatus as is used for the conversion process. In the present invention, I charge a suitable still of the type of those ordinarily known as coking stills, with a body of heavyoil such as dried and reduced crude, and add to it a certain amount of aluminum chlorid. This amount may be advantageously 5 to 10 per cent of the amount of oil. Stirring or mechanical agitation is here, because of the character of the oil, not ordinarily resorted to. I now distil, passing the vapors through a suitable device for partially cooling them with reflux of condensate to the body of oil. After this partial cooling the vapors are allowed to go to exit at a temperature not substantially above 350 F. If the exit temperature be held at 350, or in that neighborhood, no aluminum chlorid will go forward to the final condenser and such final condenser will then yield a mixture of low boiling oils which may be distilled to obtain gasoline, solvents and kerosene. If the exit temperature be held at or around 300 F, the final condensate is mostly gasoline. In partially cooling in the described manner, the aluminum chlorid is condensed together with, in the earlier stages of heating, a certain amount of high boiling oil; and the two flow 'back together to the body of Oil in the Still. I carry on the. heating to dryness, leaving a residue of coke in the still. As the process goes on, the amount of oils vaporized and capable of condensation in the cooler, diminishes until, just before the contents of the still go to dryness, there is very little vapor of heavy oil going for Ward. Aluminum chlorid, however, is volatilized, in increasing amount, and the vapors pass forward into the partial cooling system where they are condensed as before. There being, however, at this time no oil vapors co-condensed, or substantially none, the aluminum chlorid remains in the cooling system and does not go back into the still. At this time the still contains only the coked residue of the oil while the aluminum chlorid is substantially all in the cooling system. The operation is interrupted at this point, the still cleaned and recharged with oil. The oil may be sent into the still through the cooling system liquefying and carrying with it the aluminum chlorid therein contained. Or the oil may be simply charged into the still in the usual way and the still heated. Vapors of heavy oil going into the cooling system and condensing quickly wash the aluminum chlorid back into the still. As much fresh aluminum chlorid may be added to the charge in the beginning of the second heating as will suffice to compensate for any losses.

In the accompanying illustration, I have shown, more or less diagrammatically, certain apparatus useful in the described process. In this showing,

Numeral 1 indicates a furnace chamber fired in any convenient manner as by oil and gas burner 2 and heating the still 3 mounted therein. The still is provided with charging line 4 for oil and for a mixture of oil and aluminum chlorid and with manhole 5 for the purpose of charging aluminum chlorid when it is to be added in solid form. The manholes 6 and 7 at the bottom of the still are provided for the purpose of cleaning the coke when the charge has been run to dryness, the manhole 5 being opened when this is done for the purpose of providing air circulation. This still is further provided with a line 8 which is used for the admission of steam or other cooling fluid when the still is to be cooled. Mounted above the still is the cooling chamber 9 of ample capacity in communication with the still through the vapor line 10 provided with the valve seat 11, the valve 12 operated by stem 13 leading from the top of the cooling chamber. The cooling chamber is advantageously provided with a plurality of staggered baffles 14 offering obstructions in the path of the aluminum chlorid tending to flow forward through the chamber and acting in part as a dephlegmator for condensing vapors of higher boiling bodies. Leading from the condenser chamber is the vapor line 15 valved at 16 and provided with thermometer 17 ata point Where thevapors leave the cooling chamber. This line 15 leads to the final condensing coils 18 mounted in the condenser box 19. Gases pass by line 20 to a compressor or a gas holder past the seal 21 and condensate from the final condenser goes by line 22 to stock tank or storage tank, notshown.

The cooling chamber 9is provided at a high point with inlet line 23 for admission of oil and with a line 24 for venting ofi' gases during the latter stages of the heating operation.

In operation the still 3 is charged with a quantity of high boiling oil, say, reduced or dried crude which may have a Baum gravity as low as 11, if desired. Gas oil or solar oil or other distillates may, however, be used. From 5 to 10 per cent (usually over 5 per cent) of anhydrous aluminum chlorid is added. The aluminum chlorid may be mixed with the oil which is admitted to the still through inlet 4 or the aluminum chlorid may be fed in solid form to the still through the manhole 5. The line 4 may be connected to aluminum chlorid making apparatus and the vapors from such apparatus may be led directly to the still 3, but .ordinarily I prefer to admit the alumnium chlorid with the inflowing oil for the pur pose of calculation. The still is heated to a temperature causing boiling or ebullition of the contents, the still being charged to about per cent of its total capacity, and the operation is conducted at such a rate that the volume of vapors going through the vapor line 10 to the cooling chamber 9 is such that the vapors will have a temperature not above 350 F. or 300 F., depending upon the character of the product desired, at the highest point in the vapor line where the thermometer 17 is located. The valve or plug 12 is opened during this operation, the valve 16 on the vapor line 15 is opened during this operation and the valves on lines 23 and 24 are closed. The valves on the lines leading to the still and the manholes are, of course, also closed. Higher boiling oils and alumnium chlorid or aluminum chlorid in combination with the hi her boiling oils condense in the cooling amber 9 and 'reflux to the still 3; vapors of lower boiling oils going past the thermometer 17 to the final condenser coils 18, and thence to the storage tank through line 22. Any gases 7 leaving the coils 18 passes the trap or seal 21 to the gas line 20 leading to an absorber, compressor or gas tank (not shown).

The process is continued, the temperature being gradually increased as the flow of vapors tends to diminish until substantially no vapors of low boiling oil pass to the vapor line 15. This indicates that as much of the higher boiling oil as possible has been converted into the lower boiling oil of the I the still, either mechanically or chemically,

is released therefrom and passes in vapor form to the cooling chamber 9, where it is condensed. As the temperature goes up formation of volatile products ceases, and

this is indicated by the absence of as from; the line 24. This line 24 is not on y useful also useful in pre-- for this purpose, but -is venting gases, such as hydrochloric acid gases during this recovery stage from passing. to the condenser coils 18. When all available aluminum chlorid has been recovered from the coky residue, the plug 12 is lowered on the seat 11 and the cover of' manhole 5 is removed, whereupon steam .or other cooling fluid or reagent is admitted through line 8 for the purpose of cooling the still; the exhaust steam or other fluid escaping through the manhole 5 after having contacted with the residual coke and the interior walls of the still. When the still has reached a temperature sufliciently cool the manholes 6-and 7 are removed and the carbon is removed from the bottom of the still. The time required for this cooling depends, of course, upon the size of the still. A thousand barrel still can be cooled in something under .six hours. After the residual coke or carbon has been removed from the still, the manholes 5, 6 and 7 are closed, and new high boiling oil is added to the still through inlet 4. The plu 12 of the cooling. chamber 9 is opened and high boiling oil is admitted to the cooling chamber'through inlet 23, washing and removing from such cooling chamber the condensed aluminum chlorid therein and returning it to the still. This oilis advantageously used of new oil added to combined with theresidue in,

the lower boiling at a relatively high temperature, in such condition it acting to more readily remove the aluminum chlorid from the walls and lates of the condenser. The still 3 may e re-charged wholly by means of oil admitted by line 23 to the chamber 9 or some oil may be added through the inlet 4, if desired; and additional aluminum chlorid may be added to the still to manhole 5 when 1 solid aluminum chlorid is added or through the inlet 4 when this additional aluminum chlorid is added in admixture with the oil. When the still is re-charged the heating is resumed as before described and the operation is repeated. I may rely upon vapors the still for washing condensed aluminum chlorid for the condenser9.

It will thus be seen that with the same apparatus I am able to conduct the converting process and the aluminum chlorid recovery process and in doing this, the alumi num chlorid which is re-used does not'come into contact with the air or with moisture.

It is advantageous after steaming the still to cool it and after removing the carbon or coke therefrom, to aheat the still somewhat in order to dry it before additional oil is added and before the aluminum chlorid is washed back to the still from the cooling chamber 9. When the still is direct fired, the coke'removed may be used as the fuel. The cooling chamber 9 is advantageously air cooled, but other means of cooling may be adopted.

The temperature of the mixture of oil and aluminum chlorid in the still during the conversion process depends upon the character of the oil used. With heavy crude or reduced crude oil having a normal .boiling point around 600, ebullition starts in at. a somewhat lower temperature and the temperature gradually increases as the con-- version takes place. After the higher boiling oil has been completely converted,into oil desired, the still may be heated to redness, say up to 1000 F. or more for recovery. of aluminum chlorid. Metallic aluminum or aluminous material such as aluminum carbid or aluminum nitrid, capable of reacting with hydrochloric acid gas formed during the converting process or the recovery process may be added to the oil undergoing conversion. This expedient is particularly useful in the case of certain crudes containing considerable amounts of sulfur or oxygen or both. Bauxite reduced with carbon in the electric furnace gives a cheap form of finely divided aluminum particularly suitable-for this purpose. The recovery of aluminum chlorid may be facilitated by passing chlorin into the still, but ordinarily this is not desirable usually the case.

In substance I establish a heating zone (thestill) and a (cooling zone (the chamber 9), the two being connected, and through the arrangement described I trap the aluminum chlorid in the chamber 9 when it reaches such chamber substantially free of oil. After'the still is cooled and coke removed, the aluminum chlorid is returned in any of the Ways stated.

1. In the conversion of higher boiling petroleum oils into lower boiling oils with aluminum chlorid, the process which comprises establishing a heating zone and a cooling zone in connection therewith, heatmg a. mixture of aluminum chlorid and higher boiling petroleum oils in thehea'ting zone and controlling the cooling zone, during that part of the operation when substantial amounts of lower boiling hydrocarbons are produced, at such a temperature as to condense higher boiling hydrocarbons and aluminum chlorid in. the cooling zone but to allow passage of vapors of the lower boiling oils from the cooling zone, condensing such lower boiling oils, and during such stage returning condensed higher boiling oils and aluminum chlorid to the heating zone, and when production of lower boiling oils has substantially ceased, raising the emperature of the heating zone to volatilize aluminum chlorid, condensing the aluminum chlorid in the absence of any substantial amounts of oil, whereby it remains in the cooling zone, and returning said last named condensed aluminum chlorid to the heating zone for a subsequent operation.

2. In the conversion of higher boiling petroleum oils into lower boiling oils with aluminum chlorid, the process which comprises establishing a heating zone and a cooling zone in connection therewith, heating a mixture of aluminum chlorid and h gher boiling petroleum oils in the heating 'zone and controlling the cooling zone, during that part of the operation when substantial amounts of lower boiling hydrocarbons are produced, at such a temperature as to condense higher boiling hydrocarbons and aluminum chlorid in the cooling zone but to allow passage of vapors of the lower boiling oils from the cooling zone, condensing such lower boilin oils, and during such stage returning con ensed higher boiling oils and aluminum chlorid to the heating zone, and when production of lower boiling oils has substantially ceased, raising the temperature of the heating zone to volatilize aluminum chlorid, condensing the aluminum chlorid in the absence of any substantial amounts of oil, whereby it remains inthe cooling zone, and returning said last named condensed aluminum chlorid to the heating zone for a subsequent operation by flushing the same from the cooling zone with petroleum oil.

aluminum chlorid, the process which comprises establishing a heating zone and a cooling zone in connection therewith, heating a (0 mixture of aluminum chlorid and higher boiling petroleum oils in the heating zone and controlling the cooling zone, duringthat part of the operation when substantial amounts of lower boiling hydrocarbons are produced, at such a temperature as to condense higher boiling hydrocarbons and aluminum chlorid in the coolin zone but to allow passage of vapors of the ower boiling oils from the cooling zone, condensing such lower boiling oils, and during'such stage returning condensed higher boiling oils and aluminum chlorid to the heating zone, and when production of lower boiling oils has substantially ceased, raising the temperature of the heating zone to volatilize aluminum chlorid, condensing the aluminum chlorid in the absence of any substantial amounts of oil, whereby it remains in the cooling zone, and returning said last named condensed aluminum chlorid to the heating zone for a subsequent operation byflushing the same from the cooling zone with warm petroleum oil.

4. In the conversion ofhigher boiling petroleum oils into lower boiling oils with aluminum chlorid, the process which comprises establishing a heating zone and a cooling zone in connection therewith, heating a mixture of aluminum chlorid and 10" higherboiling petroleum oils in the heating zone and controlling the cooling zone, during that part of the operation when substantial amounts of lower boiling hydrocarbons are produced. at such a temperature as to 1 condense higher boiling hydrocarbons and aluminum chlorid in the cooling zone but to allow passage of vapors of the lower boiling oils from the cooling zone, condensing such lower boiling oils, and during such 1 condensed aluminum chlorid to the heating zone for a subsequent operation by flushing the same from the cooling zone with petroleum oil admitted thereto from an outside source.

5. A process in accordance with claim 1 in which residual matter in the heating zone is removed prior to the return of the aluminum chlorid thereto. 6. A process in accordance with claim 1 in which prior to the return of the aluminum mamas chlorid to the heating zone the temperature of said zone is reduced and residual matter therein is removed.

7. A process in accordance with claim 1 wherein prior to the return of the aluminum chlorid to the heating zone the temperature of said zone is reduced by admission of steam and the residual matter is removed.

8. A process in accordance with claim 1 in which additional aluminum chlorid than that returned from the cooling zone is used in the subsequent operation.

9. A process in accordance with claim 1 in which another aluminous material in addition to the aluminum chlorid is usedin admixture With the hi her boiling oil.

10. The process 0 converting higher boiling petroleum oils into lower boilin oils which comprises heating the same in a mixture with anhydrous aluminum chlorid to gradually increasing temperature, collecting and condensing the lower boiling hydrocarbons formed, and at the time the temperature reaches such a stage that the aluminum chlorid substantially free of oil is driven from the mixture, collecting and condensing such aluminum chlorid at a point removed from the mixture, removing residualmatter from the heating zone and returning the so collected aluminum chlorid thereto.

In testimony whereof, I have hereunto affixed my signature.

. ALMER MoD. MOAFEE. 

